JP3813230B2 - A method of adhesively bonding a cover to a molded stuffing made of polyurethane foam in particular - Google Patents

Abstract

Solidifying a cover onto a shaped padding, by gluing, involves arranging a cover (1) in a cold shape (2) and holding it by a frame (3), then applying a glue (4) onto the internal walls of the cover, heating the surface of the padding (5) and immediately applying the heated foam padding to the glued walls of the cover, to give immediate transfer of heat by direct contact and very rapid hardening of the glue, then opening the cold shape (2) and removing the padding provided with a cover (1).

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the field of manufacture of molded stuffing, particularly for chair cushions, and more particularly to the manufacture of chair cushions, and more particularly to a method for bonding a cover to a molded stuffing made of polyurethane foam by bonding. Is.
[0002]
[Prior art]
Placed inside the mold or molding device so that the visible surface of the chair cushion cover is aligned with the inner wall of the mold or molding device, and so placed with a pre-adhered foam or similar material molded padding By applying a certain amount of pressure against the inner wall of the cover, a foam cushion can be obtained after the adhesive has hardened, with the cover conforming to all the contours and irregularities of the foam stuffing and adhered by the adhesive. To be done.
[0003]
However, the good adhesion of molded fillings, especially molded polyurethane foams, depends on the quality of the fine molded coating that forms the surface of any molded polyurethane foam filling.
[0004]
Therefore, the filling made with a molded foam known as a low temperature cure foam where the release agent attached to the interior of the mold is a wax in a solvent solution is better during the process of attaching the foam filling to the cover. It has a preferred permeable and mostly porous surface coating for adhesion.
[0005]
On the other hand, fillings made of molded foam known as high temperature curing foam, where the release agent attached to the interior of the mold is an aqueous dispersion wax, adheres well during the operation of attaching the foam filling to the cover. This has a relatively thick, smooth, slightly permeable surface coating which is highly undesirable and requires that the coating be eliminated by brushing prior to the deposition operation.
[0006]
[Problems to be solved by the invention]
In order to economically industrialize the above method, it is necessary to shorten the time required for curing the adhesive by drying, curing or polymerization to the shortest time.
[0007]
The most commonly used joining method at present is that when the padding with adhesive is applied to the cover covering the mold or molding device, the temperature of the mold or molding device is transferred to the adhesive through the fabric. The mold or the molding apparatus is brought to a relatively high temperature of about 80 ° C. to 120 ° C. so that the adhesive can be cured.
[0008]
However, this known method has two drawbacks.
[0009]
One drawback is that it takes a long time for heat to be transferred from the mold or molding device through the dough, especially when using dough that is foamed backside with a foam layer having a thickness of 2-5 mm.
[0010]
Under these circumstances, even if a polyurethane adhesive that rapidly polymerizes is used, the curing time of the adhesive is 40 seconds to 120 seconds, and the molding apparatus cannot be moved, resulting in an increase in manufacturing cost.
[0011]
Another drawback is that the material that makes up the cover is inevitably damaged by the fact that the visible surface of the cover hits the walls of the heated mold or molding device, and so particles in the case of PVC artificial leather. Will shine and disappear, and in the case of velvet, jersey and other fabrics, will result in spots, unwanted shot-silk effects, and fiber coatings. Therefore, a so-called matting operation with a brush or dry steam is necessary.
[0012]
These drawbacks can only be overcome by lowering the temperature of the mold or molding equipment, but at the same time the adhesive cure time is increased and can be as high as 180 seconds.
[0013]
It has been proposed to transfer the temperature to the adhesive more rapidly in order to reduce the curing time of the adhesive.
[0014]
This method involves passing dry steam at a temperature of 150 ° C. to 300 ° C. through the foam filling and cover, and then through a hole drilled in the bottom of the mold or molding apparatus.
[0015]
In this method, the temperature of the dry steam is transferred more rapidly to the adhesive, reducing the curing time of the adhesive to about 30 seconds.
[0016]
However, this method also has drawbacks.
[0017]
Actually, the steam introduced into the cushion must be removed, but in order to cool and dry the inside of the cushion, the steam is sucked and then external air is blown into the vacuum source to blow the mold or molding device. Including joining the bottoms. The total time required for steam extraction and drying and curing of the adhesive is relatively long, which increases investment costs and increases manufacturing costs. Finally, hot dry steam through the fabric material can damage the fabric material.
[0018]
Furthermore, this method cannot be performed when the cover is made of an impermeable material such as PVC artificial leather or an impermeable fabric material because steam cannot pass through the cover.
[0019]
Finally, there is currently no method for securing and accurately placing the foam padding on a transport tray that contacts the foam padding with adhesive applied to a cover placed inside the molding apparatus. Then, assuming that the tray carrying the foam filling can be mechanically placed in a fully centered position of the molding device, the foam filling made of a very flexible material and without the grip keys can be It's very difficult to fully center on the above. This results in random placement and foam filling that is not completely centered on the cover will be placed inside the molding device, resulting in the resulting decoration, for example, seam or fold misalignment. The quality of the cushion, especially the appearance, is poor.
[0020]
Currently, the foam padding is centered and secured on the transport tray by one or more rigid inserts, particularly made of metal, incorporated into the foam and protruding from the foam. The protruding part of the insert can be fixed mechanically on the transport tray, ie by engagement or magnet.
[0021]
However, this type of measure hinders recycling when the cushion reaches the end of its useful life, and the metal insert must be separated from the foam in order to recycle the foam and insert separately. In addition, these disposable metal centering inserts are relatively bulky.
[0022]
The object of the present invention is to overcome these drawbacks.
[0023]
[Means for Solving the Problems]
In practice, the present invention comprises the steps of placing the cover in a room temperature forming device, fixing it to the room temperature forming device with a holding frame, and then placing the adhesive on the inner wall of the cover, Subsequently, the surface of the padding that cooperates with the inner wall of the cover is heated to a high temperature, the heating is stopped after reaching a predetermined temperature, and the heat is instantaneously transferred by direct contact with the adhesive. Immediately applying the foam filling heated to cure the adhesive very quickly to the inner wall of the cover, thereafter opening the room temperature molding device, and removing the filling with the cover attached thereto. In particular, the invention relates to a method for adhesively bonding a cover to a molded stuffing made of polyurethane foam, in particular for producing chair cushions.
[0024]
According to the invention, the method comprises the steps of first producing the foam filling by molding, and providing a cavity in which positioning and fixing means are provided on the support surface in cooperation with the transport tray, respectively. Initially positioning the molded padding on a support comprising mounting the foam padding on a transport tray and securing it in cooperation with an inflatable centering device It is also related to fixing.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
The invention will be better understood from the following description of a preferred embodiment given by way of non-limiting example and described with reference to the accompanying drawings.
[0026]
According to the present invention, as shown in detail in the examples of FIGS. 1 to 12, in particular, the joining method by bonding the cover to the stuffing formed of polyurethane foam is to arrange the cover 1 inside the room temperature molding device 2, The cover 3 is secured to the device by means of holding means 3, after which the adhesive 4 is applied to the inner wall of the cover 1 and subsequently the surface of the padding 5 intended to cooperate with the inner wall of the cover 1 to a high temperature. Heat, stop heating after reaching a predetermined temperature, immediately apply the foam filling 5 so heated to the cover 1 to which the adhesive 4 is adhered and bond the heat by direct contact with the adhesive 4 The adhesive is rapidly transmitted to the agent, and the adhesive is cured extremely rapidly. Thereafter, the room temperature molding apparatus 2 is opened, and the filling 5 provided with the cover 1 is taken out.
[0027]
The room temperature molding apparatus 2 can be equally manufactured with synthetic material, cast iron or various composite materials.
[0028]
In the example shown, the cover 1 can be composed of a woven fabric lined with a foam layer 2 mm to 5 mm thick. A portion corresponding to the periphery of the cushion made of the artificial leather sheet made of PVC 6 is sewn to the woven fabric along the seam 7. The cover 1 is placed on the molding device 2 and held in its position by the holding frame 3.
[0029]
According to a first embodiment of the present invention schematically shown in FIGS. 1 to 3, a part of the adhesive 4 pre-adhered to the foam filling 5 by spraying is formed between the foam filling 5 and the inner wall of the cover 1. Adhesive is applied indirectly by transferring during brief contact.
[0030]
Adhesive 4 is first applied to the surface of foam filling 5 by a spray gun in a dedicated, independent spraying location, such as a spraying chamber similar to a painting chamber.
[0031]
The amount of adhesive that first adheres to the surface of the foam filling 5 is 49 g to 60 g per square meter.
[0032]
FIG. 1 schematically shows a transport tray 11 and a foam filling 5 which has been wet-adhered and secured on the transport tray. Thereafter, the foam filling 5 is lowered by the transport tray 11 and brought into contact with the molding apparatus 2 including the cover 1 (FIG. 2). The foam filling 5 to which the water-containing adhesive is attached is brought into contact with the inner wall of the cover 1 and left for a short time of 0.5 second to 2 seconds. By doing so, a part of the adhesive is transferred to the inner wall of the cover 1.
[0033]
After this short time, when the transport tray 11 is lifted (FIG. 3), part of the adhesive is transferred to the inner wall of the cover 1 and the other part of the adhesive remains on the surface of the foam filling 5. In fact, only a quarter to a third is transferred during this brief contact of the foam padding 5 with the inner wall of the cover 1. Thus, according to this first embodiment of the present invention, the amount of adhesive initially applied to the foam padding 5 is between 40 g and 60 g per square meter, so that only 10 g to 20 g per square meter of the adhesive. The amount is transferred to the inner wall of the cover 1 so that an amount of 30 to 40 g of adhesive per square meter remains on the foam filling 5.
[0034]
With this very small amount of adhesive, reaching only 10 g to 20 g per square meter, which is very uniformly attached to the inner wall of the cover 1, a very good adhesion can be achieved according to the invention, The risk of defects due to collapse of the foam lining is eliminated.
[0035]
According to a second embodiment of the invention shown in FIG. 8, a spray gun in the region to be connected to the foam filling 5, in particular so as to place a very thin layer of adhesive 4 on the foam lining of the cover 1. The adhesive 4 is indirectly attached by spraying the adhesive 4 on the inner wall of the cover 1.
[0036]
The amount of adhesive thus deposited is preferably between 40 g and 60 g per square meter.
[0037]
By way of example, the adhesive used contains 100% dry extract and has two components, namely a molecular weight of 6000, such as that manufactured by Bayer and known under the trade name Bayer 3963, and a hydroxyl index (hydroxyl). A polyurethane adhesive having 70% by weight of a polyol having a 28 index of 28 or 30% by weight of a triol type polyol and 30% by weight of an MDI type isocyanate. E. D. It is activated by an A-type amine catalyst. In this case, it is preferable to use a spraying device using a two-component spray gun.
[0038]
Other adhesives such as one-component polyurethane adhesives including 100% dry extract or solvent, water phase or solvent rubber adhesives, additions of thermosetting or thermoplastic adhesives can obviously be used.
[0039]
4 and 9 schematically show the rapid heating of the surface of the foam filling 5 to bring the foam filling 5 to a temperature on the order of 170 ° C to 190 ° C.
[0040]
For this purpose, the present invention uses a box 8 in which an infrared lamp or an infrared tube 9 having a temperature of 1000 ° C. to 1400 ° C. is incorporated. The infrared lamp or tube is mounted on a support that can be adjusted relative to the bottom of the box 8 so that all of the infrared lamp or tube 9 is at the same distance from the surface of the foam comprising the padding 5.
[0041]
In accordance with the features of the present invention, it is advantageous to mount the box 8 so that it can be withdrawn between the surface of the foam filling 5 and the molding device 2 in the manner of a drawer, and an infrared lamp or tube 9 is provided between the filling 5 and the molding device 2. Supplied by a detachable device between each time the box 8 is retracted from the position. Therefore, each time the box 8 is inserted, the infrared lamp or the infrared tube 9 can be switched by a detachable device. When the box 8 is retracted (FIGS. 5 and 10), the supply of infrared light or infrared tube is automatically cut off.
[0042]
The infrared lamp or the infrared tube 9 set to 1300 ° C. emits radiation 10. The radiation brings the surface of the foam constituting the filling 5 to a temperature of about 170 ° C. to 190 ° C. after a duration of 2 seconds to 10 seconds.
[0043]
Thus, in the first embodiment, the radiation 10 brings the adhesive 4 remaining on the foam filling 5 to the same temperature of about 170 ° C to 190 ° C. The first effect of this is to melt a layer of wax that is common to the surface of all foam fillings, such as foam filling 5, and constitutes a significant portion of its molded coating. This melted wax is absorbed inside the adhesive layer and is therefore totally neutralized or almost eliminated. This polymerizes the adhesive layer at a very high temperature, and forms a fixed surface that is integrated with the porous surface of the foam filling 5 and greatly aids subsequent adhesion, such as a primer, and is slightly rough and dry. At the same time, it has the second effect of forming the layer 4bis.
[0044]
According to another characteristic of the invention, the foam constituting the stuffing 5 has a dark color, preferably a dark gray, and in the case of polyurethane foam, from 0.1 part to 1 part of colorant per 100 parts of polyol. A dark color is imparted to the foam by adding a black colorant, which advantageously consists of carbon black glued in proportions in the polyol. This coloring gives the foam adequate heat absorption capacity and thus good heat storage capacity. Therefore, a temperature of about 170 ° C. to 190 ° C. at which the surface of the foam filling 5 is heated can be achieved more easily.
[0045]
In fact, the dark gray coloration in the foam increases its emission by reducing the reflection of incident energy, thus increasing the amount of energy absorbed by the foam, which in this way is heated form Determine the heat storage capacity. In this heat storage, the temperature absorbed in this way can be used for a period of time up to 10 seconds. In other words, while the padding 5 is applied to the inner wall of the cover 1 to which the adhesive 4 is adhered inside the room temperature molding device 2. The temperature is still high enough to allow the adhesive to cure rapidly.
[0046]
The infrared lamp or, more generally, the infrared tube 9 is preferably a quartz infrared emitter having a tungsten filament that emits high-intensity infrared rays having a short wavelength of 3000 watts per tube, such as an infrared tube made by Philips. These infrared tubes are arranged at a distance of 50 mm to 200 mm from the surface of the foam filling 5 depending on the release of the dark gray colored foam.
[0047]
5 and 10 schematically show the transport tray 11 and the foam padding 5 secured thereto. The padding 5 is lowered by the transport tray 11 and comes into contact with the forming device 2 including the cover 1 to which an adhesive has been applied. For this purpose, the box 8 which functions as a drawer in this example is pulled out in 1 to 2 seconds, and at the same time, the infrared lamp or the infrared tube 9 is turned off. Accordingly, the heating is stopped, and the foam padding 5 possibly covered with a layer of polymerized adhesive forming the primer 4bis (first embodiment) and the cover 1 to which the liquid adhesive 4 is applied The transport tray 11 is lowered in 3 seconds to 4 seconds so that the total time between when making contact is between 4 seconds and 6 seconds.
[0048]
Thus, according to the first embodiment of the present invention, and the heat storage and adhesive density obtained by coloring the foam dark gray (1000 g per liter, which is the density of the foam, ie 45 g per liter. Much higher), the temperature of the polymerized adhesive layer forming the primer 4 bis when in direct contact with the adhesive 4 attached to the inner wall of the cover 1 is still 120 ° C. to 150 ° C. It is. Since this temperature is transmitted instantaneously by direct contact with the adhesive 4, it determines the polymerization time of the adhesive 4 from 5 seconds to 7 seconds. Therefore, not only the foam filling 5 colored in dark gray, but also the adhesive layer attached thereto is brought to a very high temperature to increase the heat storage due to the density of the adhesive, and thus the heating time of the adhesive. And at least one of the polymerization time is reduced by 10% to 20% (see FIG. 5), and the heat energy is completely absorbed by the adhesive 4 and the foam lining so that the temperature of the cover 1 never exceeds 40 ° C. The constituent material of the cover 1 is not affected.
[0049]
In accordance with the second embodiment of the present invention, as well as the foam being colored dark gray, the temperature of the foam when in direct contact with the adhesive 4 is still between 120 ° C. and 140 ° C. This temperature, which is transmitted instantaneously by direct contact with the adhesive 4, determines a polymerization time of 5 to 8 seconds, and the thermal energy is almost completely absorbed by the adhesive 4 and the foam lining so that the temperature of the cover 1 is 40 Since the temperature never exceeds 0 ° C., the constituent material of the cover 1 is not affected (see FIG. 10).
[0050]
Employing the first embodiment provides several advantages including the following.
[0051]
Since the adhesive is not sprayed directly on the foam filling as well as the cover, there is no problem of soiling the fabric constituting the cover.
[0052]
By spraying the adhesive on the foam filling elsewhere, the risk of clogging the mechanical parts due to the adhesive aerosol is eliminated.
[0053]
Since the adhesive layer pre-adhered to the foam filling is transferred to the inner wall of the cover by a very small amount and the adhered adhesive layer is very thin, there is a risk that the appearance will be damaged by crushing the foam lining of the cover Completely resolved.
[0054]
By heating not only the surface of the foam filling, but also the layer of adhesive remaining on the foam, it forms a common surface coating for all molded polyurethane foams Wa The first effect is to melt the wax and absorb the wax into the adhesive layer, and thus neutralize the wax, and to polymerize the adhesive layer at the same time so that it is integrated with the cellular surface of the foam filling. A second effect is obtained in that a slightly rough undercoat can be formed to greatly assist the adhesion during the fixing operation. In accordance with the present invention, a low temperature cure foam or thermoset having a thin and open permeable molded coating resulting from the release of components in a solvent solution, or a thick, smooth, almost impermeable coating resulting from the release of components in an aqueous dispersion. The foamed stuffing can be attached as well.
[0055]
The fact that not only the surface of the foam padding colored dark gray but also the layer of adhesive adhering to it is brought to a very high temperature, the density of the adhesive, i.e. 1000 g per liter, is the density of the foam, i.e. 1 liter. Because it is much higher than 45 grams per hour, at least one of the adhesive heating time and polymerization time is shortened by 10% to 20%, thus accelerating the manufacturing cycle.
[0056]
After polymerizing the adhesive, the foam padding 5 is removed from the transport tray 11 as shown in FIGS. 6 and 11 and the transport tray is raised to free the cushion. Thereafter, the frame 3 is opened, and the cushion constituted by the foam filling 5 and the cover 1 attached thereto can be taken out from the molding apparatus 2.
[0057]
The cushion with the cover attached according to the present invention is shown in FIG.
[0058]
The molding device 2 which arranges the cover 1 of the cushion is not heated.
Due to the ambient temperature of the field, the process according to the invention makes it possible to avoid damaging the material constituting the cover, i.e. woven, non-woven, PVC artificial leather, velvet or natural leather.
[0059]
Therefore, in contrast to the prior art, this method comprises the step of placing the adhesive 4 directly or via the foam filling 5 on the inner wall of the cover 1 which is pre-arranged inside the room temperature forming device 2, and thereafter Heating the pre-coated or non-coated foam padding 5 to a high temperature by radiation from an infrared lamp or infrared tube 9 and the heat from the surface of the foam padding 5 instantaneously by direct contact with the adhesive 4 Finally, the pre-coating thus heated is finally applied so that the adhesive 4 can be cured very quickly in a time of 2 seconds to 10 seconds without being affected by the material constituting the cover 1. Applying foam padding 5 with or without coating to the inner wall of the cover 1 to which the adhesive 4 has been applied. The reason why the material constituting the cover 1 is not affected in this way is that the temperature of the cover 1 never exceeds 40 ° C. as a result of the heat energy being almost completely absorbed by the adhesive 4 and the foam lining. It is.
[0060]
In order to allow the foam filling 5 to be fully positioned and secured on the transport tray 11, the method of the present invention, as shown in detail in FIGS. 7 and 9, first produces the foam filling by molding, Further comprising providing a cavity 12 in a support surface thereof intended to cooperate with the transport tray 11. Positioning and fixing means in each space As a washer 13 is provided. The means attaches the padding 5 to the transport tray 11 and secures the padding there by cooperating with the inflatable centering element 14.
[0061]
As shown in FIG. 13, the stuffing is manufactured by molding in a mold composed of a trough 15 and a lid 16. The lid 16 is, for example, attached to a hinge so that it can be placed perfectly on the trough 15.
[0062]
In accordance with a feature of the present invention, the lid 16 is provided with a stud 17. The studs are screwed or welded to the lid 16 or are integrated with the lid. Each stud is provided with a washer 13 made of a hard material and lightly press-fitted. The washer constitutes positioning and fixing means and is intended to form the filling inside the mold and remove it from the mold and then transfer it to the corresponding surface of the filling.
[0063]
The stud 17 is preferably cylindrical and has a height of 20 mm and a diameter slightly longer than 18 mm, for example, 18.1 mm to 18.3 mm.
[0064]
Depending on the dimensions of the foam filling 5, the number of studs 17 can be increased from two to eight.
[0065]
The outer diameter of the washer 13, which can be made of dense cardboard or any other hard material that can be recycled, is preferably 50 mm and the inner diameter is 18 mm, i.e. very slightly shorter than the inner diameter of the stud 17, so that Ensures that those washers are retained during molding. The thickness of these washers 18 varies from 0.5 mm to 3 mm.
[0066]
The dimensions mentioned for the stud 17 and washer 13 are not clearly limited, for example in the case of the stud 17 the height can vary from 15 mm to 30 mm and the diameter can vary from 15 mm to 25 mm, The dimensions of the washers 13 can be defined as a function of the dimensions of the studs 17 that receive those washers.
[0067]
Therefore, the polyurethane foam mixture is poured into the foam mold according to FIG. 13 and the lid 16 is closed. The foam mixture expands, fills the entire mold and partially covers the washer 13 fitted in the stud 17. The stud 17 forms the washer 13 and the concentric foam cavity 12 simultaneously.
[0068]
After foam polymerization, the lid 16 is opened and the foam filling 5 having the void 12 corresponding to the space occupied by the stud 17 of the lid 16 is removed from the mold. The washer 13 is partially tightly enclosed on the surface of the foam filling 5 at the void 12. By this manufacturing method, the washer 13 of the foam filling 5 can be completely arranged in a way that can be completely repelled.
[0069]
By this molding method including inserting a washer, the positioning and fixing hand for the foam filling 5 as described above. Step To ensure that the foam filling 5 is perfectly centered on the cover 1 when the transport tray 11 is mechanically placed on the forming device 2.
[0070]
FIG. 14 shows the transport tray 11 provided with an inflatable centering device 14. Their diameter is 16 mm and their height is equal to or less than 20 mm to match the depth of the cavity 12 defined by the stud 17. Each of these devices 14 is schematically composed of a small air jack 18 surrounded by a ring 19 made of flexible rubber or similar material. When the small jacks 18 are moved upward (FIG. 9), the jacks compress the rubber ring 19 into a substantially spherical shape with a diameter of 20 mm.
[0071]
FIG. 14 shows an easy placement of the foam filling 5 on the transport tray 11. The inner diameter of the washer 13 is larger than that of the device 14 inserted into the cavity 12.
[0072]
FIG. 15 shows the deformation of the rubber ring 19 after the jack 18 is differentiated. Such a deformation increases the diameter of the ring, on the one hand allowing the foam filling 5 to be completely centered on the transport tray 11 and on the other hand the pressure applied by the deformed ring 19 on the transport tray 11. The foam padding can be fixed on top. The foam padding 5 is released by releasing the small jack 18 and loosening the compression of the rubber ring 19. The ring, whose compression has been released, returns to its original diameter of 16 mm. The foam filling 5 is then freed according to the washer 13.
[0073]
It is clear that the dimensions described for the inflatable centering device 14 are not limiting. Device 14 is sized arbitrarily to match the dimensions of stud 17 and washer 13.
[0074]
Positioning and fixing means arranged in a completely accurate and reproducible manner on the surface of the foam forming the filling 5 The washer By providing 13, the stuffing 5 can be placed on and secured to the transport tray 11 by means of an inflatable centering device 14, so that the foam stuffing can be accurately placed on the cover and has been known so far. It is possible to avoid all of the defects that are present, that is, the seams being shifted or wrinkled.
[0075]
The present invention has been described above with respect to polyurethane foam fillings. However, the method of the invention can also be applied when the filling is composed of latex foam, rubberized hair or interwoven polyester fibers.
[0076]
Finally, Above This method can be applied to polyurethane foam, whether produced by molding or cut from a foam block.
[0077]
In accordance with the present invention, a series of operations can be performed using an ordinary temperature molding apparatus that can polymerize the adhesive between the cover and the pad almost instantaneously without causing the risk that the surface on which the cover is visible deteriorates or is damaged. This makes it possible to bond the cover to a molded pad of polyurethane foam, in particular for producing chair cushions.
[0078]
Furthermore, the padding can be placed completely in the center of the cover according to the invention.
[0079]
It will be clear that the invention is not limited to the embodiments described and shown in the accompanying drawings. Changes may be made without departing from the scope of protection of the invention, in particular with regard to the arrangement of the various elements or by replacing them with technical equivalents.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state in which a cover is arranged on a molding apparatus provided with a holding frame according to a first embodiment.
FIG. 2 is a view similar to FIG. 1 showing the operation of attaching an adhesive to the inner surface of the cover.
FIG. 3 is a view similar to FIG. 1 after the adhesive has been applied to the inner surface of the cover.
FIG. 4 is a view similar to FIGS. 1 to 3 showing the operation of heating the surface of the filling.
FIG. 5 is a reduced view similar to FIGS. 1 to 4 showing the padding applied to the inner wall of the cover.
FIG. 6 is a cross-sectional view showing a state in which the molding apparatus is opened after the cover is joined.
FIG. 7 is a cross-sectional view showing a state in which a cover is arranged on a molding apparatus provided with a holding frame according to a second embodiment.
FIG. 8 is a view similar to FIG. 7 showing the operation of attaching an adhesive to the inner surface of the cover.
FIG. 9 is a view similar to FIGS. 7 and 8 showing the operation of heating the surface of the filling.
FIG. 10 is a reduced view of a view similar to FIGS. 7 to 9 showing the padding applied to the inner wall of the cover.
FIG. 11 is a cross-sectional view showing a state in which the molding apparatus is opened after the cover is joined.
FIG. 12 is a cross-sectional view of a cushion including a cover.
FIG. 13 is a perspective view of a mold used to mold a filling with positioning and securing means.
FIG. 14 is a cross-sectional view showing the placement of foam filling on the transport tray.
FIG. 15 is a cross-sectional view showing fixation of foam stuffing onto a transport tray.
[Explanation of symbols]
1 Cover
2 Room temperature forming equipment
3 Holding frame
4 Adhesive
5 Stuffing
6 PVC
7 Seam
8 boxes
9 Infrared tube
11 Transport tray
12 voids
13 Washer
14 Centering device
18 Small air jack
19 rings

Claims (10)

A method of adhesively bonding a cover to a molded stuffing made of polyurethane foam, in particular for manufacturing a chair cushion,
Placing the cover (1) in the room temperature molding apparatus (2) and fixing it to the room temperature molding apparatus with the holding frame (3);
Foam padding part (5) pre-the deposited adhesive by spraying onto (4), by moving between the inner wall of the foam padding (5) and cover (1) is in contact briefly Indirectly attaching the adhesive (4) to the inner wall of the cover (1);
Not only does the surface of the filling (5) cooperating with the inner wall of the cover (1) rapidly heat to a high temperature, but at the same time the layer of adhesive (4) remaining on the foam filling (5) is at the same temperature. rapidly heated by the heat, whereas in the melt the layer of wax constituting the substantial part of the molded coating of the foam padding (5), on the other hand to form a fixed surface that may help in the subsequent adhesion A step of polymerizing the adhesive layer;
After reaching a predetermined temperature, heating is stopped and the heated foam filling (5) is covered (so that the adhesive is cured very quickly by direct transfer of heat by direct contact with the adhesive (4). Immediately hitting the inner wall of 1),
Method characterized by including the steps of retrieving cover (1) padding with a (5) cold forming device (2).   The method according to claim 1, characterized in that the room temperature forming device (2) is suitably constructed from synthetic material, sheet metal, cast iron or various composite materials. First, the adhesive (4) is adhered to the surface of the foam filling (5) with a spray gun, and then the foam filling (5) is brought into contact with the inner wall of the cover (1) for a short time of 0.5 second to 2 seconds. In the meantime, only one-fourth to one-third of the amount of adhesive (4) is transferred from the foam filling (5) to the inner wall of the cover (1) during this brief contact, and the inner wall of the cover (1). the method according to claim 1, characterized in that to allow the biasing deposition by in the adhesive (4) a small amount of its attached to equalizing one moved to. Foam padding (5) the amount of adhesive which is initially deposited on top of is about 40g~60g per square meter, about a small amount of adhesive per square meter that is transferred to the inner wall of the cover (1) 10G～ Method according to claim 3, characterized in that 20 g of adhesive is left on the foam filling (5) in an amount of about 30 g to 40 g per square meter.   The adhesive used is a polyol having a molecular weight of 6000 and a hydroxyl value of 28, such as 100% dry extract and having two components, i.e. known under the trade name Bayer 3963 manufactured by Bayer, or A polyurethane adhesive having 70% by weight of a polyol of a different triol type and 30% by weight of an MDI type isocyanate. E. D. The process according to any one of claims 1, 3 and 4, wherein the process is activated by an A-type amine catalyst.   The adhesive used is a one-component polyurethane adhesive with 100% dry extract or solvent addition, a water phase adhesive or solvent rubber adhesive, a thermosetting or thermoplastic adhesive. Item 5. The method according to any one of Items 1, 3, and 4.   The surface of the foam filling (5) is rapidly heated by a box (8) in which an infrared lamp or an infrared tube (9) having a temperature of 1000 ° C. to 1400 ° C. is provided, and the infrared lamp or infrared tube 2. Mounted on a support that is adjustable relative to the bottom of the box (8), so that all are at the same distance from the surface of the foam constituting the filling (5). the method of.   Using the box (8) mounted so as to be able to be pulled out and put in between the surface of the foam padding (5) and the molding device (2), the infrared lamp or the infrared tube (9) is used for the padding (5) and the molding device. 8. Method according to claim 7, characterized in that it is supplied by a device that can be detached each time the box (8) is retracted from a position between (2). The melted wax is absorbed inside the adhesive layer and completely neutralized, and the adhesive layer polymerized at high temperature is slightly rough which is integral with the cellular surface of the foam filling (5). 9. The method according to claim 1, wherein a dry layer (4bis) is formed.   The foam constituting the stuffing (5) is dark, preferably dark gray, and in the case of polyurethane foam, it is paste-like in the polyol at a ratio of 0.1 to 1 part of colorant per 100 parts of polyol. 10. A process according to any one of claims 1, 3, 4 and 7 to 9, characterized in that a dark color is imparted to the foam by adding a dark colorant which is advantageously composed of carbon black.

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